Sunday, March 1, 2015

Mortality in ADHD: a huge cohort study

You may be surprised if you know patients with Attention Deficit and hyperactivity Disorder tend to die young. Or do you think it is quite predictable?

Søren Dalsgaard et al. conducted a prospective cohort study with Danish children for some decades. They started this study in investigated almost 2 million people to diagnose them and followed them up to 2013. As a result, the mortality rate in ADHD patients was proven to be twice as high as healthy people.

ADHD is a relatively common disorder in boys. Those with ADHD have a difficulty to concentrate, often cannot stay at a place for long time, and are reckless.The severity of the symptoms is so various that some patients are overlooked in childhood.

ADHD is sometimes accompanied by other mental disorders, such as conduct disorder, substance misuse, and learning disability. The authors of this article examined the impact of ADHD on the mortality excluding the influences of other factors. After all, people with ADHD are likely to encounter an accident more frequently than those without ADHD. However, it looks like a tautology, because careless people are possible to be diagnosed with ADHD. Current standard of diagnosis of ADHD includes no objective data such as blood count or genetic examinations.

This is a shocking report. However, parents of the patients with ADHD need not to be pessimistic so much. The mortality rate is only 5.85 per 10,000 person-year. Rather, as the authors mentioned, they should be aware of the fact that ADHD is a treatable disease.

This great survey was published in Lancet, a world-famous medical journal. I am at home now, so I cannot read the original article. Notwithstanding this, I can feel the strength of this study. It is extremely difficult to continue a project for decades. A sophisticated methodology, strong motivation shared by the team, members, and a large amount of budget are required. I respect the researchers very much.

I believe that the researchers are not satisfied with publishing only this paper. A longitudinal observational study tells us many things. They must be prepared to detect other interesting findings. One of them seems to be the risk factors for schizophrenia in child and adolescent, published in Schizophrenia Bulletin.

Clinical data is a treasure of humankind. I expect the researchers to reap more fruits from this data.

By the way, it is strange that only five persons are listed up in this paper. Hundreds of researchers must be involved in this big project. Some more names should be included in the list of contributors, I think.